Historically, large airships have been characterized by a complete lack of control at low speeds and when standing still before attachment of the ship to a mooring tower. Conventional fins and movable surfaces did not provide adequate control even at elevated speeds because the controls were always too slow in response.
The concept of controlling airships by the momentum force of jets or thrusters is one which was first proposed by Forlanini, a designer of semi-rigid airships in the early part of the 20th century. Forlanini built a small airship which was controlled in all directions by a central blower from which air was ducted to the stern and the bow of the ship and there released in jets of air by valving at appropriate times. Control by this means was sufficiently effective to allow the airship to be maneuvered into the hanger without the help of a ground crew. The use of a central blower as the source of jet air is, however too cumbersome and heavy for use in airships, particularly large airships.
Conventional control arrangements and mechanisms are also unsatisfactory for efficient operation of airships, particularly metal-clad airships. Such orthodox control surfaces are harmful to airship performance and, particularly are incapable of providing fully dependable and effective control of the ship at all speeds from zero speed forward to maximum. They are, likewise, essentially totally ineffective in controlling the airship in turbulent weather, lacking as they do, dependability and responsiveness